Development of a novel moisture sensor based on superabsorbent poly(acrylamide)-montmorillonite composite hydrogels

The time dependence of water vapour absorption by superabsorbent polymer cl ay composite (SAPC) hydrogels was studied using thermophysical methods. For the purpose of comparison the average value of the specific interaction en thalpy of liquid water with the SAPC structure was calorimetrically determi ned for a defined interaction time. Dynamic vapour absorption measurements confirmed that the SAPC material has a sufficiently high absorption capacit y and good selectivity for water vapour. A prototype moisture sensor with e xcellent reproducibility of the output voltage signal was constructed by co ating a silicon integrated thermotransducer with a thin SAPC membrane. (C) 2001 Kluwer Academic Publishers.